Optical lens

Abstract

An optical lens having, in total, six lenses which sequentially comprise from an object side to an imaging surface (S15) along an optical axis: a first lens (L1) having a negative focal power, an object-side surface (S1) thereof being a convex surface, and an image-side surface (S2) thereof being a concave surface; a second lens (L2) having a positive focal power, an object-side surface (S3) and an image-side surface (S4) thereof both being convex surfaces; a third lens (L3) having a positive focal power, an object-side surface (S5) thereof being a convex surface, and an image-side surface (S6) thereof being a concave surface; and a fourth lens (L4) having a negative focal power, an object-side surface (S7) and an image-side surface (S8) thereof both being concave surfaces; a fifth lens (L5) having a positive focal power, an object-side surface (S9) and an image-side surface (S10) thereof both being convex surfaces; and a sixth lens (L6) having a negative focal power, an object-side surface (S11) thereof being a convex surface, and an image-side surface (S12) being a concave surface. An effective focal length f of the optical lens and the radius of curvature R6 of the image-side surface of the third lens (L3) satisfy: R6 / f>14.0. By means of the reasonable configuration of surface type of each lens and the reasonable focal-power combination in the optical lens, the resolution of the optical lens is improved, and the aberration is reduced, thus improving the imaging quality of the optical lens.

Description

Optical lens

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese application No. 2023107904985, filed on June 30, 2023, which is incorporated herein by reference in its entirety for all purposes. Technical Field

[0003] The present application relates to the technical field of imaging lenses, and in particular to an optical lens. Background Art

[0004] As people's requirements for driving experience continue to increase, automotive optical lenses are increasingly used in intelligent driving, and the status of automotive optical lenses in the automotive-related industries continues to improve.

[0005] Advanced Driver Assistance Systems (ADAS) play a crucial role in intelligent driving. They use a variety of lenses and sensors to collect environmental information to ensure driver safety. Existing ADAS surround-view lenses require not only a thin, compact form factor with high pixel count and resolution, but also the ability to produce clear images in low-light conditions. Therefore, developing an optical lens with excellent imaging performance is crucial.

[0006] Application Contents

[0007] In view of the above problems, the purpose of this application is to provide an optical lens with the advantage of excellent imaging quality.

[0008] The present application provides an optical lens having a total of six lenses, which are arranged in order from the object side to the imaging surface along the optical axis:

[0009] a first lens having negative optical power, wherein the object-side surface is convex and the image-side surface is concave;

[0010] a second lens having positive refractive power, wherein both the object-side surface and the image-side surface are convex;

[0011] The third lens has positive optical power, its object-side surface is convex and its image-side surface is concave;

[0012] a fourth lens element having negative optical power, wherein both the object-side surface and the image-side surface are concave;

[0013] The fifth lens has positive refractive power, and both the object-side surface and the image-side surface are convex;

[0014] a sixth lens element having negative optical power, the object-side surface of which is convex and the image-side surface of which is concave;

[0015] The effective focal length f of the optical lens and the image side curvature radius R6 of the third lens satisfy: R6 / f>14.0.

[0016] Further preferably, the object-side curvature radius R5 and the image-side curvature radius R6 of the third lens satisfy: -1<(R5-R6) / (R5+R6)<0.

[0017] Further preferably, the image side sag height Sag6 of the third lens and the image side semi-aperture d6 satisfy: -0.12 <Sag6 / d6<0。

[0018] Further preferably, the total optical length TTL and the effective focal length f of the optical lens satisfy: 3.0 <TTL / f<5.5。

[0019] Further preferably, the effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view satisfy: 0.5<(IH / 2) / (f×tan(FOV / 2))<0.75.

[0020] Further preferably, the effective focal length f of the optical lens and the real image height IH corresponding to the maximum field angle satisfy: 1.5 <IH / f<2.5。

[0021] Further preferably, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 <f1 / f<-1.0。

[0022] Further preferably, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.0 <f2 / f<2.0。

[0023] Further preferably, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.0 <f3 / f<2.8。

[0024] Further preferably, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.5 <f4 / f<-1.0。

[0025] The optical lens provided in this application can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. Through the reasonable configuration of the surface shapes of each lens and the reasonable matching of the optical focal length, the resolution of the optical lens is improved, the aberration is reduced, and the imaging quality of the optical lens is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0027] FIG1 is a schematic structural diagram of the optical lens in Example 1 of the present application.

[0028] FIG2 is a field curvature curve diagram of the optical lens in Example 1 of the present application.

[0029] FIG3 is a diagram showing the F-tanθ distortion curve of the optical lens in Example 1 of the present application.

[0030] FIG4 is an MTF curve diagram of the optical lens in Example 1 of the present application.

[0031] FIG5 is a relative illumination curve diagram of the optical lens in Example 1 of the present application.

[0032] FIG6 is a graph showing an axial aberration curve of the optical lens in Example 1 of the present application.

[0033] FIG7 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 1 of the present application.

[0034] FIG8 is a schematic structural diagram of the optical lens in Example 2 of the present application.

[0035] FIG9 is a field curvature curve diagram of the optical lens in Example 2 of the present application.

[0036] FIG10 is a diagram showing the F-tanθ distortion curve of the optical lens in Example 2 of the present application.

[0037] FIG11 is an MTF curve diagram of the optical lens in Example 2 of the present application.

[0038] FIG12 is a relative illumination curve diagram of the optical lens in Example 2 of the present application.

[0039] FIG13 is a graph showing an axial aberration curve of the optical lens in Example 2 of the present application.

[0040] FIG14 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 2 of the present application.

[0041] Figure 15 is a schematic structural diagram of the optical lens in Example 3 of the present application.

[0042] FIG16 is a graph showing the field curvature of the optical lens in Example 3 of the present application.

[0043] FIG17 is a diagram showing the F-tanθ distortion curve of the optical lens in Example 3 of the present application.

[0044] FIG18 is an MTF curve diagram of the optical lens in Example 3 of the present application.

[0045] FIG19 is a relative illumination curve diagram of the optical lens in Example 3 of the present application.

[0046] FIG20 is a graph showing the axial aberration of the optical lens in Example 3 of the present application.

[0047] FIG21 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 3 of the present application.

[0048] Figure 22 is a schematic diagram of the structure of the optical lens in Example 4 of the present application.

[0049] Figure 23 is a field curvature curve diagram of the optical lens in Example 4 of the present application.

[0050] Figure 24 is an F-tanθ distortion curve of the optical lens in Example 4 of the present application.

[0051] Figure 25 is an MTF curve diagram of the optical lens in Example 4 of the present application.

[0052] Figure 26 is a relative illumination curve of the optical lens in Example 4 of the present application.

[0053] Figure 27 is an axial aberration curve diagram of the optical lens in Example 4 of the present application.

[0054] FIG28 is a vertical axis chromatic aberration curve diagram of the optical lens in Example 4 of the present application.

[0055] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0056] For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely descriptions of embodiments of the present application and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0057] It should be noted that in this specification, the terms "first," "second," "third," etc., are used solely to distinguish one feature from another and do not limit the features. Thus, the first lens discussed below could also be referred to as the second lens or the third lens without departing from the teachings of this application.

[0058] In the drawings, the thickness, size, and shape of the lenses are slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical and aspherical surfaces shown in the drawings are provided by way of example. That is, the shapes of the spherical and aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0059] In this article, the paraxial region refers to the area near the optical axis. If a lens surface is convex and the location of the convex surface is undefined, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the location of the concave surface is undefined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the subject is called the object-side surface of the lens, and the surface of each lens closest to the imaging plane is called the image-side surface of the lens.

[0060] It should also be understood that the terms "comprises," "including," "having," "includes," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. In addition, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features rather than modifying the individual elements in the list. In addition, when describing embodiments of the present application, "may" is used to mean "one or more embodiments of the present application." And, the term "exemplary" is intended to refer to an example or illustration.

[0061] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and will not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

[0062] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0063] The optical lens according to the embodiment of the present application includes, in order from the object side to the image side along the optical axis: a first lens, a second lens, an aperture, a third lens, a fourth lens, a fifth lens, a sixth lens, and a filter.

[0064] In some embodiments, the first lens element may have negative power to reduce the angle of incident light, effectively sharing the large object-side field of view. The first lens element has a convex object-side surface and a concave image-side surface, which helps collect as much light from the edge of the field of view as possible and feed it into the rear optical element, achieving wide-angle light collection.

[0065] In some embodiments, the second lens element can have positive optical power, which helps converge light while reducing light deflection angles and ensuring a smooth transition. Both the object and image side surfaces of the second lens element are convex, balancing various aberrations produced by the optical lens and improving imaging quality.

[0066] In some embodiments, the third lens may have a positive focal power, which is beneficial to further converge light while reducing the light deflection angle and enabling a smooth transition of the light path. The object side surface of the third lens is convex, and the image side surface is concave, which can reduce the impact of spherical aberration and astigmatism generated by the third lens itself on the optical lens and improve the imaging quality of the optical lens.

[0067] In some embodiments, the fourth lens may have a negative focal power, and both its object side surface and image side surface are concave, which is beneficial to balance various aberrations generated by the optical lens and improve the imaging quality of the optical lens.

[0068] In some embodiments, the fifth lens may have a positive focal power, which is beneficial to improve the light converging ability of the optical lens. Both its object side surface and image side surface are convex, which can reduce the spherical aberration and coma generated by the fifth lens itself and improve the imaging quality of the optical lens.

[0069] In some embodiments, the sixth lens may have a negative focal power, which is beneficial to increase the imaging area of the optical lens and improve the imaging quality of the optical lens. The object side surface of the sixth lens is convex, and the image side surface is concave, which can optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

[0070] In some embodiments, the effective focal length f of the optical lens and the curvature radius R6 of the image side surface of the third lens satisfy: R6 / f > 14.0. Meeting the above range, by adjusting the curvature radius of the image side surface of the third lens, the surface shape of the image side surface of the third lens can be appropriately adjusted, which can reduce the impact of spherical aberration and astigmatism generated by the third lens itself on the optical lens and improve the imaging quality of the optical lens.

[0071] In some embodiments, the curvature radius R5 of the object side surface and the curvature radius R6 of the image side surface of the third lens satisfy: -1 < (R5 - R6) / (R5 + R6) < 0. Meeting the above range, by adjusting the curvature radii of the object side surface and the image side surface of the third lens, the deflection degree of light passing through the lens can be alleviated, which can reduce the impact of aberrations generated by the third lens on the optical lens and improve the imaging quality of the optical lens.

[0072] In some embodiments, the sagittal height Sag6 of the image side surface and the clear aperture radius d6 of the image side surface of the third lens satisfy: -0.12 < Sag6 / d6 < 0. Meeting the above range, by adjusting the off-axis area surface shape of the image side surface of the third lens, various aberrations in the edge field of view of the optical lens can be effectively improved, and the imaging quality of the edge field of view of the optical lens can be improved.

[0073] In some embodiments, the overall optical length TTL of the optical lens and the effective focal length f satisfy: 3.0 < TTL / f < 5.5. Meeting the above range, it can effectively limit the length of the lens and achieve miniaturization of the optical lens.

[0074] In some embodiments, the effective focal length f of the optical lens, the maximum field angle FOV, and the true image height IH corresponding to the maximum field angle satisfy: 0.5 < (IH / 2) / (f×tan(FOV / 2)) < 0.75. Meeting the above range is beneficial for the optical lens to achieve a balance between the field angle size and the F-tanθ distortion size, and improve the imaging quality of the optical lens.

[0075] In some embodiments, the effective focal length f of the optical lens and the true image height IH corresponding to the maximum field angle satisfy: 1.5 < IH / f < 2.5. Meeting the above range is beneficial for the optical lens to achieve a balance between the field angle size and the F-tanθ distortion size, and improve the imaging quality of the optical lens.

[0076] In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 < f1 / f < -1.0. Meeting the above range can make the first lens have a small negative optical power, which is beneficial for increasing the field angle of the optical lens. At the same time, the refraction angle change of the incident light is relatively gentle, avoiding excessive aberration caused by overly strong refraction changes, and improving the imaging quality of the optical lens.

[0077] In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.0 < f2 / f < 2.0. Meeting the above range can make the second lens have an appropriate positive optical power, which is beneficial for the convergence of light rays, enabling the divergent light rays entering the system from the front to smoothly enter the rear optical system, making the light ray trend smoother, optimizing aberration, and improving resolution.

[0078] In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.0 < f3 / f < 2.8. Meeting the above range can make the third lens have an appropriate positive optical power, and can reduce the influence of spherical aberration and astigmatism generated by the third lens itself on the optical lens, and improve the imaging quality of the optical lens.

[0079] In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.5 < f4 / f < -1.0. Meeting the above range can make the fourth lens have an appropriate negative optical power, which is beneficial for balancing various aberrations generated by the optical lens, and improving the imaging quality of the optical lens.

[0080] In some embodiments, the effective focal length f of the optical lens and the focal length f5 of the fifth lens satisfy: 0.8 < f5 / f < 1.2. Meeting the above range can make the fifth lens have an appropriate positive optical power, and can reduce the spherical aberration and coma generated by the fifth lens itself, and improve the imaging quality of the optical lens.

[0081] In some embodiments, the effective focal length f of the optical lens and the focal length f6 of the sixth lens satisfy: -2.5 < f6 / f < -1.3. Meeting the above range can endow the sixth lens with an appropriate negative optical power, which is beneficial to increasing the imaging area of the optical lens. Meanwhile, it can optimize the chromatic aberration of the optical lens and improve the imaging quality of the optical lens.

[0082] In some embodiments, the maximum field of view FOV of the optical lens satisfies: 95° < FOV < 135°. Meeting the above range can enable the optical lens to have a large field of view.

[0083] In some embodiments, the maximum field of view FOV of the optical lens and the f-number FNO satisfy: 40° < FOV / FNO < 65°. Meeting the above range is beneficial to expanding the field of view of the optical lens and increasing the aperture of the optical lens, which is conducive to the optical lens obtaining more scene information and meeting the requirements of large-range detection. The realization of the large-aperture characteristic is beneficial to improving the problem of rapid decline of the relative brightness in the edge field of view, and thus is also conducive to obtaining more scene information.

[0084] In some embodiments, the overall optical length TTL of the optical lens and the true image height IH corresponding to the maximum field of view satisfy: 2.0 < TTL / IH < 2.5. Meeting the above range can effectively balance the requirements of the image height and miniaturization of the optical lens.

[0085] In some embodiments, the true image height IH corresponding to the maximum field of view of the optical lens and the entrance pupil diameter EPD satisfy: 3.5 < IH / EPD < 5.0. Meeting the above range can increase the width of the light beam entering the optical lens, improve the brightness at the image plane of the optical lens, and avoid the generation of vignetting.

[0086] In some embodiments, the maximum field of view FOV of the optical lens, the true image height IH corresponding to the maximum field of view, and the clear aperture D1 of the object side surface of the first lens satisfy: 0.4 < D1 / IH / tan(FOV / 2) < 0.8. Meeting the above range can ensure the balance among the size of the optical lens, the field of view, and the image plane.

[0087] To enable the system to have better optical performance, multiple aspherical lenses are used in the lens. The shapes of the aspherical surfaces of the optical lens satisfy the following equation:

[0088]

[0088] where z is the distance between the curved surface and the vertex of the curved surface in the optical axis direction, h is the distance from the optical axis to the curved surface, c is the curvature of the vertex of the curved surface, K is the conic coefficient, and A, B, C, D, E, and F are the surface coefficients of the second order, fourth order, sixth order, eighth order, tenth order, and twelfth order respectively.

[0089] The present application is further described below with reference to a number of embodiments. In each embodiment, the thickness, radius of curvature, and material selection of each lens in the optical lens vary. For details, please refer to the parameter tables of each embodiment. The following embodiments are merely preferred embodiments of the present application, but the embodiments of the present application are not limited solely to the following embodiments. Any other changes, substitutions, combinations, or simplifications that do not deviate from the innovative aspects of the present application shall be deemed equivalent replacements and are included within the scope of protection of the present application.

[0090] Example 1

[0091] Please refer to Figure 1, which is a schematic diagram of the structure of the optical lens provided in Example 1 of the present application. The optical lens includes, from the object side to the imaging surface along the optical axis, a first lens L1, a second lens L2, an aperture ST, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, and a filter G1.

[0092] The first lens L1 has negative refractive power, its object-side surface S1 is convex, and its image-side surface S2 is concave;

[0093] The second lens L2 has positive refractive power, and its object-side surface S3 and image-side surface S4 are both convex;

[0094] Aperture ST;

[0095] The third lens L3 has positive refractive power, its object-side surface S5 is convex, and its image-side surface S6 is concave;

[0096] The fourth lens L4 has negative refractive power, and its object-side surface S7 and image-side surface S8 are both concave;

[0097] The fifth lens L5 has positive refractive power, and its object-side surface S9 and image-side surface S10 are both convex;

[0098] The sixth lens L6 has negative refractive power, its object-side surface S11 is convex, and its image-side surface S12 is concave;

[0099] The object-side surface S13 and the image-side surface S14 of the filter G1 are both flat surfaces;

[0100] The imaging surface S15 is a plane.

[0101] The relevant parameters of each lens in the optical lens in Example 1 are shown in Table 1-1.

[0102] Table 1-1

[0103] The surface parameters of the aspheric lens of the optical lens in Example 1 are shown in Table 1-2.

[0104] Table 1-2

[0105] In this embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative illumination curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown in Figures 2, 3, 4, 5, 6, and 7, respectively.

[0106] Figure 2 shows the field curvature curves of Example 1, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within a range of -0.09mm to 0.1mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0107] Figure 3 shows the F-Tanθ distortion curve for Example 1, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging surface. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within a range of -40% to 0%, and the image compression in the edge angle region is relatively smooth, effectively improving the clarity of the expanded image.

[0108] Figure 4 shows the MTF (Modulation Transfer Function) curve of Example 1, which represents the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF value of this embodiment is above 0.5 across the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0109] Figure 5 shows the relative illumination curve of Example 1, which represents the relative illumination values ​​at different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0110] Figure 6 shows a graph of the axial aberration of Example 1, which shows the aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within -30μm to 40μm, indicating that the optical lens can effectively correct axial aberration.

[0111] Figure 7 shows a graph of vertical chromatic aberration for Example 1, plotting the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -2 μm to 8 μm, demonstrating that this optical lens is capable of excellently correcting chromatic aberration in the peripheral field of view and the secondary spectrum across the entire image plane.

[0112] Example 2

[0113] Please refer to Figure 8, which is a schematic structural diagram of the optical lens provided in Example 2 of the present application. Compared with Example 1, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0114] The relevant parameters of each lens in the optical lens in Example 2 are shown in Table 2-1.

[0115] Table 2-1

[0116] The surface parameters of the aspheric lens of the optical lens in Example 2 are shown in Table 2-2.

[0117] Table 2-2

[0118] In this embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative illumination curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown in Figures 9, 10, 11, 12, 13, and 14, respectively.

[0119] Figure 9 shows the field curvature curves for Example 2, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within a range of -0.09mm to 0.1mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0120] Figure 10 shows the F-Tanθ distortion curve for Example 2, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging surface. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within a range of -30% to 0%, and the image compression in the edge angle area is relatively smooth, effectively improving the clarity of the expanded image.

[0121] Figure 11 shows the MTF (Modulation Transfer Function) curve of Example 2, which represents the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF values ​​of this embodiment are consistently above 0.4 across the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0122] Figure 12 shows the relative illumination curve of Example 2, which represents the relative illumination values ​​at different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0123] Figure 13 shows a graph of the axial aberration of Example 2, which plots the aberrations along the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the graph, the offset of the axial aberration is controlled within a range of -30 μm to 15 μm, indicating that the optical lens is capable of effectively correcting axial aberrations.

[0124] Figure 14 shows a graph of vertical chromatic aberration for Example 2, plotting the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -2 μm to 8 μm, demonstrating that this optical lens is capable of excellently correcting chromatic aberration in the peripheral field of view and the secondary spectrum across the entire image plane.

[0125] Example 3

[0126] Please refer to Figure 15, which is a schematic structural diagram of the optical lens provided in Example 3 of the present application. Compared with Example 1, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0127] The relevant parameters of each lens in the optical lens in Example 3 are shown in Table 3-1.

[0128] Table 3-1

[0129] The surface parameters of the aspheric lens of the optical lens in Example 3 are shown in Table 3-2.

[0130] Table 3-2

[0131] In this embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative illumination curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown in Figures 16, 17, 18, 19, 20, and 21, respectively.

[0132] Figure 16 shows the field curvature curves for Example 3, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within a range of -0.03mm to 0.09mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0133] Figure 17 shows the F-Tanθ distortion curve for Example 3, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within a range of -50% to 0%, and the image compression in the edge angle region is relatively smooth, effectively improving the clarity of the expanded image.

[0134] Figure 18 shows the MTF (Modulation Transfer Function) curve of Example 3, which represents the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF values ​​of this embodiment are consistently above 0.5 across the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0135] Figure 19 shows the relative illumination curve of Example 3, which represents the relative illumination values ​​at different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0136] Figure 20 shows a graph of the axial aberration of Example 3, which shows the aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within a range of -15μm to 45μm, indicating that the optical lens is able to correct axial aberration well.

[0137] Figure 21 shows a graph of vertical chromatic aberration for Example 3, plotting the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -2 μm to 10 μm, demonstrating that this optical lens is capable of excellently correcting chromatic aberration in the peripheral field of view and the secondary spectrum across the entire image plane.

[0138] Example 4

[0139] Please refer to Figure 22, which is a schematic structural diagram of the optical lens provided in Example 4 of the present application. Compared with Example 1, this embodiment is different mainly in optical parameters such as the curvature radius of each lens surface and the lens thickness.

[0140] The relevant parameters of each lens in the optical lens in Example 4 are shown in Table 4-1.

[0141] Table 4-1

[0142] The surface parameters of the aspheric lens of the optical lens in Example 4 are shown in Table 4-2.

[0143] Table 4-2

[0144] In this embodiment, the field curvature curve, F-Tanθ distortion curve, MTF curve, relative illumination curve, axial aberration curve, and vertical chromatic aberration curve of the optical lens are shown in Figures 23, 24, 25, 26, 27, and 28, respectively.

[0145] Figure 23 shows the field curvature curves for Example 4, representing the degree of curvature of light of different wavelengths in the meridional and sagittal image planes. The horizontal axis represents the offset (unit: mm), and the vertical axis represents the half field angle (unit: degrees). As can be seen from the figure, the field curvature of the meridional and sagittal image planes is controlled within a range of -0.03mm to 0.12mm, demonstrating that the optical lens is capable of effectively correcting field curvature.

[0146] Figure 24 shows the F-Tanθ distortion curve for Example 4, which represents the F-Tanθ distortion of light of different wavelengths at different image heights on the imaging plane. The horizontal axis represents F-Tanθ distortion (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the figure, the F-Tanθ distortion of the optical lens is controlled within a range of -30% to 0%, and the image compression in the edge angle region is relatively smooth, effectively improving the clarity of the expanded image.

[0147] Figure 25 shows the MTF (Modulation Transfer Function) curve of Example 4, which represents the degree of lens imaging modulation at different spatial frequencies across the field of view. The horizontal axis represents spatial frequency (unit: lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF values ​​of this embodiment are above 0.5 across the entire field of view. Within the range of 0 to 160 lp / mm, the MTF curve decreases evenly and smoothly from the center to the edge of the field of view, demonstrating excellent imaging quality and detail resolution at both low and high frequencies.

[0148] Figure 26 shows the relative illumination curve of Example 4, which represents the relative illumination values ​​at different field angles on the imaging plane. The horizontal axis represents the half field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the relative illumination value of the optical lens is still greater than 70% at the maximum half field angle, indicating that the optical lens has good relative illumination.

[0149] Figure 27 shows a graph of the axial aberration of Example 4, which shows the aberration on the optical axis at the imaging plane for each wavelength. The horizontal axis represents the axial aberration value (unit: μm), and the vertical axis represents the normalized pupil radius. As can be seen from the figure, the offset of the axial aberration is controlled within a range of -15μm to 50μm, indicating that the optical lens is able to effectively correct axial aberration.

[0150] Figure 28 shows a graph of vertical chromatic aberration for Example 4, plotting the chromatic aberration of each wavelength relative to the central wavelength (0.55 μm) at different image heights on the imaging plane. The horizontal axis represents the vertical chromatic aberration value of each wavelength relative to the central wavelength (unit: μm), and the vertical axis represents the normalized field of view angle. As can be seen from the graph, the vertical chromatic aberration for both the longest and shortest wavelengths is controlled within a range of -2 μm to 8 μm, demonstrating that this optical lens is capable of excellently correcting chromatic aberration in the peripheral field of view and the secondary spectrum across the entire image plane.

[0151] Please refer to Table 5, which shows the optical characteristics corresponding to the above embodiments, including the effective focal length f, total optical length TTL, aperture value FNO, true image height IH and maximum field of view FOV of the optical lens, as well as the numerical values ​​corresponding to each conditional expression in each embodiment.

[0152] Table 5

[0153] In summary, the optical lens provided by the present application can effectively limit the length of the lens, which is conducive to the miniaturization of the optical lens. By rationally configuring the surface shapes of each lens and rationally matching the optical focal length, the resolution of the optical lens can be improved, the aberration can be reduced, and the imaging quality of the optical lens can be improved.

[0154] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0155] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that variations and improvements are possible within the scope of the present invention, and such variations and improvements are within the scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An optical lens, comprising six lenses, characterized in that: Along the optical axis from the object side to the imaging surface: The first lens has a negative optical power, and its object side surface is convex and its image side surface is concave; The second lens has positive refractive power, and its object side surface and image side surface are both convex; The third lens has positive power, its object side surface is convex and its image side surface is concave; The fourth lens element has negative optical power, and both the object side surface and the image side surface are concave; A fifth lens having positive refractive power, whose object-side surface and image-side surface are both convex; a sixth lens having negative optical power, whose object side surface is convex and whose image side surface is concave; The effective focal length f of the optical lens and the image side curvature radius R6 of the third lens satisfy: R6 / f>14.

0.

2. The optical lens according to claim 1, characterized in that: The object side curvature radius R5 and the image side curvature radius R6 of the third lens satisfy: -1<(R5-R6) / (R5+R6)<0.

3. The optical lens according to claim 1, characterized in that: The image side sag height Sag6 of the third lens and the image side light semi-aperture d6 satisfy: -0.12 <Sag6 / d6<0。 4. The optical lens according to claim 1, characterized in that: The total optical length TTL and the effective focal length f of the optical lens satisfy: 3.0 <TTL / f<5.5。 5. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens, the maximum field of view FOV, and the real image height IH corresponding to the maximum field of view satisfy the following conditions: 0.5<(IH / 2) / (f×tan(FOV / 2))<0.

75.

6. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the real image height IH corresponding to the maximum field of view satisfy: 1.5 <IH / f<2.5。 7. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: -1.7 <f1 / f<-1.0。 8. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: 1.0 <f2 / f<2.0。 9. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: 2.0 <f3 / f<2.8。 10. The optical lens according to claim 1, characterized in that: The effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: -1.5 <f4 / f<-1.0。

Images